Step-by-Step

Mac List Ports Used By Process

To find the process that is listening to a port on Mac OS X, we’ll use the lsof command to find the process ID (PID), and the ps command to show the name.

Find the Process ID (PID)

• Mac OSX - What program is using port 8080. Thank you very much 🙂 Just a suggestion. You wrote down “The name “java” doesn’t tell you anything, to get the detail, ps the java PID 12895 like this:”.
• Using GeekTool and lsof, you can display an automatically updated list of open network connections directly on a Mac OS X desktop. This is tip is a “safe” alternative to the previously mentioned openports utility.

There are two different ways we can use to find the process that is listening to a port on Mac OS X.

On my system, to find which port is being used by a process with process id 9260, I run netstat -aon findstr 9260 As you can see in the above output, process 9260 is using port 8080.

You can watch all open network connections for both incoming and outgoing transfers using a free command line utility called openports.sh. OpenPorts is much more useful than using lsof to list open internet connections because it provides extensive network information in a very easy to read format, including what program or process is opening the connection, which port and user, the number of connections per process, the hostname being connected to, the country, and even the city. We have a daemon process that handles requests made from apps running in user sessions. These requests are submitted via mach ports. The 'client' app is third-party, so it has a different signing cert etc. Currently, the app can be sandboxed and just needs to include a particular application group entitlement, and mach port IPC works fine.

Find the Process ID (PID) Using lsof

Using the lsof command we can find the process ID (PID) for a specific port that is in a LISTEN state. In a terminal type the following and replace the “<port-number>” with our port number.

This generates output that looks like this:

In the output above the PID (process ID) is the second value, in this example output the process ID (PID) is “63851”. This command will also print out the port number, which is 9999 in the above output example.

Find the Process ID (PID) Using netstat

Using the nestat command we can find the process ID (PID) for a specific port. In a terminal type the following and replace the “<port-number>” with our port number.

This generates output that looks like this:

In the output above the PID (process ID) is the ninth value (the fourth value from the end), in this example output the process ID (PID) is “63851”. This command will also print out the port number, which is 9999 in the above output example.

Find the Process Name

We can now use the process status command ps to display the process name for the process ID (PID).

This generates output that looks like this:

In the output above the process name is the last value “the-process.” Now we know the name of the process that is listening to the port. The reason as to why the grep command is listed twice is to avoid displaying the process ID (PID) for the grep command itself.

Other Useful Commands

How to Kill or Stop the Process by PID

You can kill the process by process ID (PID) using the kill command. Replace “<PID>” with the process ID from lsof or netstat.

The lsof Command

The lsof command lists open files. Network sockets count as files, so each open network socket, either listening or actively in use is listed by lsof. In addtion you can run the man lsof command to display all the different options for lsof.

lsof can take a very long time to execute, so I suggest that you use -n (inhibits the conversion of network numbers to host names for network files) and -P (inhibits the conversion of port numbers to port names for network files) to speed it up.

All-mighty Mac system monitor

When your Mac slows down or starts behaving erratically, chances are it's because an application that's running, perhaps in the background, is misbehaving. And if it's not an application that's causing the problem, it will almost certainly be a process associated with macOS or an ancillary service.

Solving this problem is usually as simple as killing the process, but in order to do that you need to identify which one.Here's a comprehensive guide on how to view and kill processes on your Mac.

Best task killers for Mac

Try the best tools that help you find and kill processes hampering your Mac's performance.

How to show which processes consume a lot of memory

The easiest way to view all active processes running on your Mac is to launch Activity Monitor from your Applications folder. In the default CPU tab, you can see how much processing power every process takes, ranked by the most consuming. And if you switch to the Memory tab, you will see the same list ranked by the amount of used up RAM.

For more immediate and elaborate information on how your computer resources are consumed, use iStat Menus, which handily lives in your menu bar and, in its MEM table, shows you applications and processes that are consuming more than their fair share of RAM in real time.

How to kill process using Activity Monitor

1. Launch Activity Monitor.
   The easiest way to launch Activity Monitor is to press Command and spacebar to call up Spotlight, then start typing Activity Monitor. When it appears in Spotlight, hit Return to launch it. Alternatively, go to Utilities in the Applications folder and double-click on its icon. Or open Activity Monitor in one click through iStat Menus app.
2. View and filter tasks.
   You'll notice there are five tabs across the top of the Activity Monitor window: CPU, Energy, Memory, Disk, and Network. Clicking on any of those tabs organizes processes according to the percentage of the resource they are using. So, clicking on CPU lists tasks in the order of how much CPU capacity they're using. By default, processes are ordered starting with the one that's consuming the most of the resource at the top, so you can quickly see where problems are occurring or likely to occur. To flip the order, so that processes consuming the least of the resource are at the top, click the arrow next to Memory or CPU above the list of processes.
   
3. Kill problematic processes.
   When you identify a process that's causing a problem, either because it's hogging lots of CPU cycles or memory, or because it's highlighted in the Activity Monitor as having crashed, you need to kill it. To do that, click on the process first and then on the X in the Activity Monitor toolbar. The process will quit and free up the resources it was taking up. If it's a critical process, it will restart. If it's an application, it will remain shut down.

Activity Monitor alternatives

Get an advanced system monitor for macOS – an improved alternative to the default program.

How to shut down processes using Terminal

1. Launch Terminal. Press Command and spacebar to pull up Spotlight then start typing Terminal. When the Terminal app appears in Spotlight, tap Return to launch it. Alternatively, navigate to the Utilities folder in Applications and double-click Terminal.
2. View processes. When Terminal has launched, type 'top' into the Terminal window. You'll see a list of currently running processes. At the top of the list is an overview of the processes that are running and the resources they're consuming.
3. Kill an unwanted process. When you identify a process that's causing a problem or consuming too many resources, take note of the number in the PID column next to the name of the process. To kill the process, type 'kill -9' followed by the PID number. Press Enter. The problem process will now quit.

How to prevent problematic processes

You can pretty much avoid issues altogether by being a little bit proactive in hunting down the common culprits. Here, iStat Menus will help you identify which applications or processes are consuming finite resources, such as CPU and RAM.

Then, you can use CleanMyMac maintenance routines that, when run regularly, will keep you Mac running smoothly. Here's how to do that:

1. Launch Setapp and search for CleanMyMac.
2. Find the maintenance scripts. Under the Speed section in the left sidebar, click on Maintenance. You will see a list of tasks that CleanMyMac would suggest you to perform to optimize your Mac. You should try to run them all, but the one especially important for us is under Run Maintenance Scripts.
3. Run the maintenance scripts. Click on the checkbox next to Run Maintenance Scripts and then click Run. Alternatively, choose another specific maintenance script such as Speed Up Mail or Reindex Spotlight and click Run. When it's finished, click Select Tasks to return to the list of maintenance tasks.

Run other tasks, as necessary. If you're having problems with Mail, repeat step 3, but this time click the checkbox next to Speed Up Mail. Likewise, if Spotlight is running slowly, run the Reindex Spotlight task.

How to kill a background process

To kill a background process, use Activity Monitor. While the steps are the same as described in the 'How to kill a running process using Activity Monitor' section above, the key difference is that background processes often have obscure names that don't clearly describe what they do.

Be careful when killing a background process and, if not sure, leave it alone or search online for its exact role in your system. Otherwise, you might risk causes problems for your macOS. Generally, background processes don't tend to consume significant RAM or CPU cycles, so if you spot one that does, it has probably got into trouble. Kill it using the X in the Activity Monitor toolbar.

How to easily remove startup items

One common cause of Macs running slowly or having problems is items that launch automatically at startup. These could be helper apps for something like iTunes or just complete apps in their own right. They are also frequently apps you once used but no longer need.

To review the apps and helpers that startup when you log in

1. Launch System Preferences from the Apple menu and click on the Users & Groups pane.
2. Click the padlock and type in your password.
3. Then select your username in the left panel and click the Login Items tab.
4. Look through all the login items that correspond to apps you no longer use and then click the minus button. The app will no longer start up automatically when you log in.

How to Force Quit an application that's not responding

If you see the dreaded spinning beachball, or an app just won't do anything, you should force quit it.

There are several ways to force quit an unresponsive application:

Macos List Ports

1. Press Command-Alt-Esc and click on the application in the window that opens. Press Force Quit
2. Control-click or right-click on the application's icon in the Dock and choose Force Quit
3. Launch Activity Monitor, locate the application and press the 'x' in the toolbar
4. Locate the process in Activity monitor, look for the entry in the PID column and launch Terminal. Type 'kill -9' followed by the PID number. Press Enter

Fix crashing apps with Spindump

While Force Quit will fix the problem, it’s a temporary solution. If you’re determined to identify the source of crashing apps and prevent them from happening, use Spindump on Mac. It’s a hang reporting tool that alerts you about the crash and helps share the details with the app developer.

Whenever the app crashes, it will trigger Spindump and send the information to Apple or the app developer. Not only does it help you understand what just happened, but it also helps the developer track the conditions of app misbehavior — and fix it accordingly. A win-win.

How to create a Spindump file on Mac

1. Launch Activity Monitor via Applications > Utilities
2. Pick the app for which you want to create a Spindump file, then click on the Settings icon
3. Select Spindump or Run Spindump
4. Wait a few seconds for the file to generate
5. Click Save.

Reset a problematic app

There's one more thing you can try if an app keeps running slowly or crashing – reset it. Thanks to CleanMyMac, resetting an app is easy. Here's what you need to do:

1. Locate the uninstaller. In the left hand sidebar of CleanMyMac, click on Uninstaller under Applications.
2. Find the app that's causing a problem. Scroll through the list of apps until you find the one that's been crashing or running slowly. Click on it to highlight.
3. Reset the app. With the app highlighted, you'll see all the files associated with it in the right-hand window. Click Application Reset at the top of the window and all the files, except the main application file, will be selected.
4. Click Uninstall. All the selected files will be trashed, effectively resetting the application to its default state. When you launch it the next time, it will behave as if it has just been installed — so you'll need to recreate any custom settings or preferences.

If resetting the app doesn't work, the final resort should be to uninstall the app completely and reinstall it. To do that, click Complete Uninstallation in the same menu instead of Application Reset.

As you can see there are lots of different ways and apps that help you view and kill processes in macOS. iStat Menus is a great way to passively monitor which processes are causing problems, so you can launch Activity Monitor and quit them. And running CleanMyMac's maintenance scripts regularly prevents problems occurring in the first place. Best of all, all these apps are available to try for free on Setapp, along with over 200 high-quality macOS apps. So check your Mac for problematic processes now and see what you find.

Meantime, prepare for all the awesome things you can do with Setapp.

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Macos List Ports In Use